The ordinary water bed comprises a bed frame including a flat horizontal mattress supporting platform and vertical side and end boards about the platform to retain a flotation mattress atop the platform within the confines of said boards. The ordinary flotation mattress is a water filled bladder of flexible plastic sheet material.
In the art of water beds, it is common practice to provide electric resistance heaters to heat and maintain the flotation mattresses at a desired temperature. The resistance heaters most commonly used in combination with water beds are flat blanket type heater units. These heater units are commonly laid flat between the bottom of the flotation mattresses and the supporting platforms of the bed frames.
It is also common practice to provide manually adjustable temperature control means for the heater units. The control means for water bed heaters generally include neat and compact box-like control units in which temperature control circuits are housed and which include a manually operable control knob accessible at the exterior of the box-like units. The control units are commonly connected with a power service cord extending from a power service outlet and are connected with the heaters by elongate power cords which extend from the control units into the bed structures and to the heaters. In addition to the above, many control means further include heat sensing devices engaged between the mattresses and the platforms and connected with the control units by elongate conductors.
The side boards of ordinary water bed frames are of considerable vertical extent, define extensive exterior surface and are established of wood or other construction materials which afford desirable supporting structures on which the heater control units can be effectively mounted as by screw fastener means. As a result of the foregoing, most commercially available water bed heater control units are small box-like units especially designed and constructed to be screw fastened to the exterior surfaces of the side boards of common water bed frames.
In the water bed art, there now exists water beds which consist of lower common or conventional box-spring units or platform units upholstered to appear as box springs, flotation mattress retaining means or units atop the box-spring units and flotation mattresses on and within the box-spring and retaining units. These water beds are commonly referred to or called hybrid water beds since they utilize certain components or parts of both common beds and water beds and seek to attain certain of the desirable attributes of both conventional and water beds. Specifically, in such water beds, the vertical extent or depth of the flotation mattresses are materially less than the vertical extent or depth of conventional water bed mattresses. This greatly reduces the volume and weight of water used. The reduced depth and volume of water also reduces the extent to which the water can surge in the resulting bed constructions and reduces undesirable residual wave action commonly experienced in such beds. The reduced volume and weight or mass of water also enables hybrid beds to be used in places where heavier conventional water bed structures cannot be used or are prohibited. Still further, hybrid bed structures require less time and energy to heat the mattresses.
As noted above, in hybrid water beds, conventional box-spring-like units are utilized. Conventional box-springs generally include lower flat horizontal rectangular wood frames which include laterally spaced longitudinally extending side beams, thin flat horizontal upper pads of soft flexible fibres in a fabric envelope spaced above the frames, a plurality of vertically compressible springs between the frames and the pads and flexible fabric covers about the exterior of and enclosing the assembled frames, pads and springs or like appearing platforms.
The flotation mattress retaining means or units provided for hybrid water beds vary widely in form. Such retaining means or units generally include horizontal rectangular weirs of resilient foam plastic engaged above and extending about the perimeters of the box-springs and central sheet-like lines of flexible plastic which overlie the box-spring units, inward of the weirs and which have edge portions which envelope the weirs and retain them in desired working position. In other retaining means or units, the weirs are established of tubular frames of heavy gauge flexible plastic sheet material, filled with water.
The flotation mattresses in hybrid water bed structures are simple bladders of flexible plastic sheet material slackily filled with water and are arranged in the upwardly opening recesses defined by the retaining units.
The heaters means provided to heat hybrid water beds commonly include flat horizontal blanket-type resistance heaters arranged between the tops of the box-spring units and the central sheet-like liners of the mattress retaining units to occur inward of the weirs and below the mattresses. The power cords for the heaters extend laterally outwardly from between the box-spring and the retaining units and connect with the small box-like temperature control units. Temperature sensing devices, which connect with the control units are also engaged between the box-springs and the mattress retaining units.
While the details of construction of the several components and/or parts of hybrid beds produced by different bed manufacturers vary considerably, the structure noted in the preceding is representative of most hybrid water beds, when considered in their broad aspects.
One characteristic found in the overwhelming majority of hybrid water bed structures is the absence of any structurally sound, hard and/or firm exterior or side surface of sufficient area or extent upon which the temperature control units can be effectively mounted and supported. The vertical exterior sides of the box-spring units are fabric and may be subject to flexure when the box-springs are yieldingly depressed and such that control units cannot be mounted therein. The vertical exterior sides of the mattress retaining units, defined by the weirs of those units, are soft and flexible and cannot be utilized as a support or mounting structure for anything.
Accordingly, neither the box-spring-like units, the retaining units, mattresses or bed frames of hybrid water beds of the general character referred to above present or normally provide any structure suitable for mounting the box-like control units provided for water bed heater means.